ML18026B110

U.S.Nrc Regulatory Perspective on Aircraft Impact Assessments

ML18026B110
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Issue date:	01/26/2018
From:	Dennis Andrukat Office of New Reactors
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U.S.NRCRegulatoryPerspec tive onAircraftImpa c tAss e s smentsDennis AndrukatU.S. Nuclear Regulatory Commission, Office of New Reactors 2Presenta summ a ryof t heU.S.NRC asse ssments bei ng cond uctedfor the n e wreact o rdesi g ns un d er 10CFR 50.1 50 ,"AircraftImp act As sessment"(AIA)Purpose 3*Bac k g r o u nd on NRCAIAreg u l at i on a n d g u i d a n c e*Summa r y of in d u s try g u i d a nce(NEI 0 7-13)*NRC i nsp ecti o n pr oce dure*Exp e rie n c e w i th De si g n C ert i fic at i on a p p l ic antsOverview

• Immediately af t er9/11/01, N RC evaluatedrepre s en tati v e e xistingrea ctorsforaircraftimpact ut ilizing Na tional Labs(200 1-20 0 4)*Regulatory requirements for aircraft impact mitigation were imposed on existing reactors via NRC Orders

• SpentFuel P ool swere evaluated

In terfacedwith NAS(200 5-2 0 07)*NRC in-house preliminary e valuationsof newrea c to r design s(AP1000, A B W R , E SBWR, E PR, and A P W R)utilizing RESstaff(200 6-2008)4Assessment of Existing and New Reactors

• N R Camend e ditsregulationtocodify NRC O r ders to mi tigatethe ef f e cts ofloss e sof lar g eareas oftheplanttofires orexplosio n s (1 0 CFR 50.54 (hh))(2009)*ALLreactors*mitigation strategies

• N R Camend e ditsregulationtorequi r eappli cantsfor new nu clear po w errea ctorsto pe rform an a s s e s s m e nt ofthe ef f e cts ofthe impact of alarge,commercialair craft(10CFR 50.150)(2009)*NEWreactor designs only

• design features and functional capabilities 5Assessment of Existing and New Reactors 610 CFR 50.150 "Aircraft Impact Assessment

"*Published June 2009

• AIA rule ap pli es t o newreacto r a pp licants af t erJuly 1 3 , 2009**Impact of a l a r ge , comm erci a l a ircr aftis a b e y ond-desig n-b a sisevent*U s e r e alistic a n a l y s es*Both safety-related and nonsafety-related features can be relied upon*Reduced use of operator action is a goal*[74 FR 28146, June 12, 2009]AIA Regulation 710 CFR 50.150(a) "Aircraft Impact Assessment "Id e nt ify a n d i n c o r p o rate intothe d e s i gnth o sefe atu r es a n d f u nc t i o n a l c a p a bil ities to sh owthat:*the r e a ctorcore remai ns co o l edOR t h e c onta i nment remai n s inta c tAND*Spent fuel pool cooling OR spent fuel pool integrity is maintainedAIA Regulation 810 CFR 50.150(b) "Content of application"This section discusses the what must be documented in the DCD

• Must identify & describethe credited key design features and functional capabilities from the assessment

• Must describe howeach key design feature and functional capability meets the rule*What is its role(s)

• Which acceptance criterion/criteria is applicableAIA Regulation 910 CFR 50.150(c) "Control of Changes"This section discusses the change control process required for key design features credited to meet 10 CFR 50.150.

• Any plant design change evaluated against the AIA

• Change must not invalidate the AIAAIA Regulation R egulatory Guide1.217*IssuedAugust2011*Endor s esNEI 07-13,"Methodologyfor Perfor mingAirc raft I m pa c t As s e s s mentsfor NewPlantDe sign s"whichwasdeveloped byNEI andrev iewed bythe N RC staff*Con side r edinsightsgainedfrom N RC and indu stry a s s e s s ments of ope rating andnew rea ctor de signs*Provides an a c c eptable, reasonably formulatedmethodologyto a s s e ssthe ef f e cts of a large , c ommercial air craftimpact on newrea ctordesign s10NRC Regulatory Guidance NEI 07-13, Revision 8

• IssuedApril2011*Methodologydivided intothree pa r t s:-Conta inment and s pent fuelpool evaluat i on-Heatremovalevaluat i on-Design enhan cements*Sour c es of c o n serva t i s m-Centerl i ne c onta inmentstri k es-Normalimpact withmaximumforce-Nocredit forlargeequipment in lim itingdamage 11Industry Guidance NEI 07-13, Revision 8

• Unc ertainties-Definition ofthreat and l oa d-time fun ction-Fire-indu c edspuriousactuat i on-10 C F R 50.5 4 (hh)(2),"Loss ofLargeArea s"of theplant due tofire or e xplosionprov i de amea sure of defen s e-i n-depth12Industry Guidance 13*Metho d ol o gy in N E I 0 7-13is acombin ation of a n a l ys i s a n drulesets-S tructu r alanalysisfor a s s e s sing c ontainment&s pent fuel poolintegrity(lo c al andglobal e ffects)-Rule setsfor a s s e s singfire and s h o c k ef f e cts-Rule setsfor a s s e s singphysi c aldamagetobuildings otherthan c ontainment and s p entfuel poolstr uctures-U s e offini te elementanalysiswhererule s ets donot apply-Based uponexperiments,analysisrepo rts, andexpert judgementAIA Methodology 14AIA Analysis Process 15 T hr e e p o te ntialsta ges o f l ocal l o a d i n g*M i ss ile penetrati o n i nto the t a r ge t (dep th o f entry of themiss ile i nto thetar get) -N R DC Emp iric a lFormu l a*S p a l l i ng a n d sca b b i ngof the t ar get (e jecti o nof tar get mater i alfrom t he tar get fro n tface -sp a l l i n g a nd from the b a ck face -sca b b i n g)-R e d uced C h a n g Emp iric a lFormu l a*M i ss ile perfor a ti o nthr oug hthe t a r ge t-Miss i leful ly p e n etratesthe t ar g et-P erforati o n ve l oc i tyis themissi l e ve l oc i ty j u stsuffici e nt toful l y p e n etrate with o ut e xiti n g-R e si d u a l ve l oc i tyis the e x it ve l oc i tyof a miss i le with i niti a l ve l oc ity gr e at e r th a n perf orati o n ve l oc i ty-CE A-EDF Empir icalFormu l a-Prev enti o nof p erforati o n-R e d uced D e g e n Emp iric a lFormu l aLocal Structural Assessment Riera Fun c t i on Te s ts*Eng ine Tests-G E-J7 9engine-481mph(705 f t/s)-2'-5.25'thicktargets*F-4Test-8'dia meter-481mph(705 f t/s)-12'thicktarget16See ADAMS Accession No. ML112690136 for more publically

-available informationAIA Experiments Wa t erSlug(WS) TestsNote: WStestswereNOTintendedtosimulate a ctualmis silesor targets*Testsdemonstra t eddamagepoten tial of"s of t"missile*Te stsprovided s o meinsightrega rdingfluiddispe r s a lis s ues*U s edto ben chmark c o des17AIA Experiments 18 T w o Alt e rn ative A n a l ysisMet h o d s*Force T im e-H istory A n a l ysisMet h od-R ieraFu nctio n:Imp a ctforce time-h istoryis d etermi n edfrom aircr a ft mass d istrib utio n ,crus h i n gstre ngthinf ormati o n a n d im p u lse co nserv ation pr i nc i p les,ass u mi n g th at t he tar get is rig i d-Prov i d e sforce t im e-h istory with sp ecific ch aract eristics-Pr e scr ibe dto de si g ne rs by U S N R C(SGI i nform a ti on)*Miss i l e-T ar get Int eracti o n A n a l ysisMet h od-C o mb i n e d d y n amic a n a l ysis mo d elof b oth missi l e a n dtar g et-R e q u ir e s d e mo nstrati o n th a t:*Inte grat e dforc e-time h istory (im p u lse)matc hes o r e x ce eds pr e scri b ed R iera fu nctionimp ulse*R i g i d w a l l im pact re p ro d uc e s ch aract eristicsof pr e scri b ed R iera fu nction ch aract eristics(res p o n sefilter e d at 50 to 1 0 0Hz)Global StructuralAssessm e nt 19 Te c hni c alSuppo r t andDetailsProvidedinNEI 0 7-13,Appendix B Material S trengthPrope rties Ta k e In t o Ac c ount:*S trainrate ef f e cts*Dynamicincrea s efactors*Con creteagingstrengthinc reaseMaterialFailure C riteria*Cast and S tainle s s S teel platestr ainlimi t s*Reinfor cing S teel strainlimi t s*Reinfor c ed andPre stre ssedCon cretefailuremodelingMaterial Characterization and Failure Criteria 20ContainmentAnal y s e s*Air craft andengineimpactperpendiculartostru ctu r ecenterline

• Po tential c ontainmentdomeimpa c tis aplan t-s p e cif i c c o n side ration*Fre e-sta ndingsteel c ontainmentsmayrequi r eairframemodel*Newplantdesignsmayconta i ndesignfea turesforwhi c hpastexperienceislacking,withpotentialfailuremodesoutsidetheexistingexperience ba s e*Regions ofthe c ontainmentwith poten tiallycritical pen etrations requi r e s p e cial c o n side rationStructural Assessment:Major Assumptions 21SpentFuel Pool Analyses*Engine andair craftfuselageimpact at mi d-height and mi d-s p an ofthe poolwall*Otherlocationswithgreaterdamagepotential s hould be a s s e s s e d*Engine andair craftfuselageimpactperpendiculartothewall s urfa c e*If c reditistaken of poolwaterinven tory, c a re s hould be exer cisedin as suringthatthe add e dmass ofthewateris modeled c o n serva t i vely*Po tentialdamagefromwallmotion onfuel a s s emblies adja c enttothewalls s hould beevaluatedStructural Assessment:Major Assumptions 22 C ontai nmentIntact*Thecontainmentremai n s i ntact if structural an alys e s performed showthatperforationof a steel conta inmentor c oncrete conta inment w ith steel l iner do e s notoccur on impactAND t hattheconta inment ultimate pressurecap a bi lity,giv e n a core damage ev ent, w o uld n o t be e x ce e d e d b efore ef fecti v e mitigati o n st rateg ies canbe impl emented*Effectivemitigati o n st rateg ies are those that,foran i ndefi niteperi o dof time,providesufficie n tcoo l i n gto the d amag e dcore or co ntai nmentto l imit temperature a n dpressure chal l en g es be l owthe ultimate pressurecap a bi lityof theconta inmentas defi n edin D CD/F S AR C hapter 19.Structural Assessment:Sufficiency Criteria 23 S pent Fuel P o olIntegrity*Loc a l izedcrushing and c racki n gof theconcrete wall of the po o lis acce ptableprovid e dthatno l eaka ge through the spe n tfuel po o l l i nercompromisesthe requ iredminimumwater l evelof the po o l*Ifthefuel po o l l i ner do es nothavea l eaka g epath b e l o wthemin imum w ater l e ve l ,thefuelis protected andthere w ou l d be no unacc eptab l erele a seof radi o nuc l i d esto the env ironment*Anaircraft impact at anelev ation be l owthespe n tfuel p o ol w iththe p otenti a lfor ca u si n g su b se q u ent co l l apse ofthe spent fuel po o lsup porting st ructure must be eva luated,as appropri ateStructural Assessment:Sufficiency Criteria 24*S tructu r al orphysi c aldamagedetermined u singrule s etsin NEI 07-13*Thephysi c aldamagerule s etsidenti fied we r e de r i v ed ba s ed on studies ofstr uctu r e swith typical reinfor c ed c o n cretewalls rep resen t ativ e of e xistingplantdesign s:-24inch ex teriorwalls, 18inchinteriorwalls*Some newplantsemploystr ucturessimilartothose of c u r rent plants,othershavestr ucturesthataresignificantlymorerobu st.*Ifthe a ctualstr ucturetobe analyzedvariessignificantl y, "Mis sil e-Targ e tIn tera c t i on A nal ysis Method"should be employedtodeterminethenumber ofreinfor c ed c o n cretewalls ne c e s s a r ytostopfurther pe rforationintothestr uctu r e on a de sign-s peci fic ba sis.Structural Assessment:Buildings Other than Containment and Spent Fuel Pool 25*T hefre q u ency sp ectrum ass o ci ated with anaircr aftimp a ctis co n si d er a b l y h i g h erth an the sp ectrum ass o ci ated with e arth q u akes.*All e q u i pm e nt with i nthe sh ock d a ma g efo otpri n tis ass umedto fa il at the timeof im pact.*R ulesets inNEI 0 7-13are us e dto d efinethe sh o ckaffectsfor six cat e g o ri e sof e q u i pm e nt b ased on f ra g i lit y.*T he sh ock d a ma g e d ista ncesare me asur e dfrom t he ce nter of i niti al im pact a n dth e n a l o nga structur al p ath w a yto theaffect e d e q u i p me nt (i.e., sh o ckis tra nsmitted t hr o u g h w a lls,flo ors a n d ce i l i n g s b u t n ot acr oss o p en a i r sp ace).*NSSS ve n d o rs h a vethe o ption of us i ngtheval u esfor SD1 t hr o u gh S D 6 co ntaine dinNEI 0 7-1 3 or d e v e l o p i n gth eir o w n dist an c e s ba s ed onacc e l erati o n va l u e sfilter e dat 2 00 Hz for sp ecificim pact l ocati ons.Shock DamageAssessm e nt 26*Fire s preadrule s etsprovidedin NEI 0 7-13*Rule setsare ba s ed onpreviousres earchrepo rts and experiments

• Fire damage footprint starts where physical damage ends -interface boundary

• Rule set consists of either the 1

-barrier option or two

-barrier option

• 1-barrier utilizes 5 psid, 3-hour fire rated barriers

• 2-barrier utilize 3-hour fire rated barriers*Firedamage sp r eadis as s es s edinall 3dimensionsFi re DamageAssessm ent 27*Firedamage c a n ex t endwellbeyondthephysi callydamag e d area duetotheoverp r e s su r e ef f e ctsfromtheinitial fireball and the s pread offuelthrough openpathw a yswithin t hestr uctu r e.*Ventilatio n duct w o r kinth e physical d a ma g efootp rintis expectedto beseverely c rush e d ,torn, and/orsevered.*Eachfiredamagefoo tprintisfullyencap sulatedwith 3-hourfirerated ba rrie r s (walls,floor s , c eilings).Encaps ulationisintendedto c ontain:-Fire/The rmal ef f e cts-Fuel Spread-Overp ress u refromdeflagr ationFi re DamageAssessm ent Fi re DamageAssessm ent28*Allcabling a n delect rical equip me ntwithin damage footprints:

• infire damage footprint

-available for five minutes only*in physical damage footprint

-lost upon impact

• A ventilation controlled internal fire will burn for several hours, thus preventing operations personnel from being able to take manual actions in these areas for several hours.*Additional considerations:

• Evaluate st ructu r alsteel n otencasedinconcrete*Smoke/Heat at air intakes C o m positeDamage F ootprint29*The c ompo sitedamagefoo tprintfor ea c himpa c tlocation s c ena riois developed byenvelopingtheto tal damagefrom str uctural,fire, and s h o c kdamage*As eachimpa c tlocation s c ena riois evaluated,thesystemicand funct i onal ef fectsthatarepre cludingprotection ofthefuel (reactor vessel and spent fuel pool) s hould be identi fiedFire DamageShock DamagePhysical Damage C o m positeDamage F ootprint30*U singplantinformation s u ch asfireanalyses,firePRAs,internal floodingstudie s , andplantdrawing s ,therule s ets and methodologywillthendeterminewhich s p e cif i cequipment, including c able s ,is a s s umedto bedamag e d*Thecombinedlist ofdamagedcables and SS Cs de finesthe threattomaintaining c ooling offuelin t heves s el and s p entfuel pool*As eachimpa c tlocation s c ena riois evaluated,thesystemic and funct i onal ef fectsthatarepre cludingprotection ofthefuel (reactor vessel and spent fuel pool) s houldbe identi fied 31Des ign Enh anc ementsPlant Design, Rev X+1Assess perNEI 07-13Identify existing/new featuresIncorporate into Design

• Ruleacceptancecriteria must be met forall postu latedimpact l ocationscen arios*10 CFR 5 0.150requ ires ap p l icantsto i de ntify andincorporate des i gnfeatures andfunctional cap a bi liti e sto meet theacceptance criteria*A p p lic ants sh o u l d d ocume n tthe ratio n a l eforthe se lected ap proach(s) 32*Three categoriesof e nh ancements-Prevent i ngIn ternalDamage*S trengthening ex ternalwalls orrelocatingintervening str uctures-MinimizingIn ternalDamage*Relocateequipment,str engtheninternalwalls, add and/or upg r adefire doo r s-Desig n-Specific S ystemEnhan cements*I mplementsystem enh a n ceme ntstofacilita t emaintaini n g fuel c oolingDes ign Enh ancements

• Appli c a n tsare not re q ui r ed to s u bmit t h e a c t ual as s e s sm e nt of t h e a i r craftimpact*As s e s s m e n t s will be s u bj e ct to in s pectio n*NRC m aytak e a p p r o pr i a t e e nf o r ceme nt a c ti o n f o r a ny v i o l a t i o n s , in cl u d i ng t h epreparat io n o f a n i nadequat eassessment orfailu re to p r e p a r e an a ss e s s m ent33Inspection Activities NRC Inspection Manual InspectionPro c edu r e 378 0 4*Mo s t-r e ce n t r evisi o n(Fe b r uary 2 0 1 2)*Verify t hat ap plic a ntide n t i f ied and in c o r p o r a t e din t othe d esignall t he n ec e s sary d esignfeatures a n dfun ctional c a p a bili tiesthat p rovide a ddition a lin h e r e nt p rote ctionto withstand ai rc r aftimp ac t*Verify re alismin a ss e s s m e nt of stru ctu ral, fire, s hock , a n d pl a nt s p ecif i clo s s ef f e cts*Verify AIA do c um entationisbeing mai ntained c o ns i stent withthe r e q uir e me nts oftherule34Inspection Procedure 35*Westi n g h o u se AP1 0 00*Gen eral El ectric Hi tachiESBWR*AREVA EPR*Tosh i baABWR (So u thTexas)*GEH Renewal ABWR

• Mi tsubishi US-APWR*KHNP APR1400Experience with Design Certification Applicants 36*Appl ying Fire DamageRule Se t s*5psidfire ba rrie r sversus 5p s idfire doors*Clo s earrange m ent of ba rrie r s und e r tw o-ba rrieroption*Ph y si cal andFirefoo tprintinterface a s s umptions and requi rements*Fireintru sion v i a ex ternalwall impacts*Use of Intervening Structures

• Gantry C r anes to beevaluated*Mesh Size AnalysisLessons Learned 37*Documentation

• Identi f y i ngALL c redited k e y de signfea tures*Everything credited in assessment must be identified in DC application

• Needed support equipment must be included*Balancinglevel ofdetailrequi r edin DCDwithoutinclusionof unn e c e s s ar y SUNSI orSGIinformationLessons Learned 38*AIArule ap p l i esto n ewreactor a pp l ic antsafter Ju ly 13, 20 0 9**I mpactof alargecommercial aircraft is a beyo n d des i gn bas i seve n t*A p pl icantsto use real istic an alys e sto i de ntifyimp o rta n t d e si g nfeatures*N R C en dorsed N E I 0 7-13 as an acceptab l e method f ormeetingthe rule*Metho ds andresults are inspected

• Lesso n s l earnedused inupdatingregu latory gu i da n ce andinsp ectionproceduresConclusion 39 Aircraft Impact Assessment rule:

https://www.gpo.gov/fdsys/pkg/FR

-2009-06-12/pdf/E9-13582.pdfAircraft Impact Assessment Inspection s: https://www.nrc.gov/reactors/new

-reactors/oversight/aia

-inspections.html#insrptRG 1.217: ML092900004NEI 07-13, Revision 8P: ML111440006Center for Nuclear Waste Regulatory Analyses' Response of Reinforced Concrete Structures to Aircraft Crash Impact: ML112690136Links 40ABWRAdvanced Boiling

-Water ReactorAIAaircraft impact assessmentAP1000Advanced Passive 1000APR1400Advanced Power Reactor 1400APWRAdvanced Pressurized

-Water ReactorCEA-EDFFrench Alternative Energies and Atomic Energy Commission

-Électricité de FranceCOLcombined license CFRCode of Federal RegisterDIFdynamic increase factors DCdesign certification DCDdesign certification document EPREvolutionary Pressurized

-Water ReactorESBWREconomic Simplified Boiling

-Water ReactorFSARfinal safety analysis report GEGeneral Electric GEH GE-HitachiKHNPKorea Hydro & Nuclear PowerNASNational Academy of Sciences NRDCNatural Resources Defense CouncilNEINuclear Energy Institute NRCNuclear Regulatory CommissionPSIDpressure per square inch differentialPRAprobabilistic risk assessmentRESOffice of Research (NRC)

RGregulatory guideSFPspend fuel pool SGIsafeguards informationSNLSandia National LaboratoriesSUNSIsensitive unclassified non

-safeguards information WSwater slugAcronyms Than k you.Questions??41